Each year approximately 100,000 elderly Americans undergo carotid endarterectomy (CEA) to reduce their risk of stroke and death. This procedure involves an open surgical incision and may be associated with substantial risks of morbidity and mortality. A promising and innovative alternative to CEA is carotid angioplasty and stenting (CAS), a minimally-invasive, endovascular procedure that may be of particular benefit in high-risk patients. Since its initial approval by the Food and Drug Administration (FDA) in 2004, the use of CAS has disseminated rapidly across the United States. Despite growing enthusiasm for this procedure, data on its use and outcomes in the "real-world" are limited. It is unknown, for example, whether CAS is being used mostly as a substitute for CEA in high- risk patients or if it is being performed in patients who might otherwise not have been treated at all. Moreover, the choice to use CAS may also be heavily influenced by which types of physician specialists are performing it. CAS is performed not just by vascular surgeons, but by interventional cardiologists and radiologists - physicians not traditionally involved with CEA or stroke care in general. As suggested by research in other cardiovascular procedures, physician specialty and experience could be important determinants of procedure use, as well as patient outcomes. An improved understanding of these issues would have important implications for clinicians, policy- makers, and payers. Indeed, the Centers for Medicare &Medicaid Services (CMS) recently considered substantial modifications to its current national coverage decision for CAS. Discussions by CMS centered not only on expanding the possible indications for this procedure, but restricting the types of physician specialists who could determine its appropriateness in any individual patient. In this context, we propose to study two-related specific aims. Specific Aim 1 will examine the dissemination of CAS in healthcare markets across the United States. Specific Aim 2 will assess real- world outcomes of CAS in the elderly. For this proposal, we will use national Medicare data (2004-2007) and are particularly interested in the role of physician specialty and experience in use and outcomes of CAS. We anticipate our findings will inform policy-makers, payers, providers, and patients struggling to determine the role of this innovative procedure. PUBLIC HEALTH RELEVANCE: Each year approximately 100,000 elderly Americans with severe carotid artery stenosis undergo carotid endarterectomy (CEA) to reduce their risk of stroke and death. A promising and innovative alternative to CEA is carotid angioplasty and stenting (CAS), but little is known about the (1) use and (2) outcomes of this minimally-invasive procedure in the real world. We anticipate that findings from this study will add new knowledge to both these areas and help inform policy-makers, payers, providers and patients struggling to determine the optimal role of CAS in preventing stroke and death.